Notable changes:
* Docker is no longer bundled with Usernetes (126), because the Docker upstreamm has been supporting Rootless mode since v19.03. To install Rootless Docker, see https://get.docker.com/rootless . See also https://docs.docker.com/engine/security/rootless/ for the further information.
* Migrated from go-task into systemd (133).
* Migrated from runc into crun for the ease of the future support of cgroup v2 (128).
* Migrated from native/vfs into fuse-overlayfs (138). Requires kernel >= 4.18.
Note: The binary is missing for this release due to a bug in the release script. Use [v20200304.2](https://github.com/rootless-containers/usernetes/releases/tag/v20200304.2).